One of the key processes in solid phase chemical synthesis is the washing of the solid support resin which has a chemical template attached thereto. Multiple washing cycles with different solvents ensures that all excess reagents used during reaction cycles are washed from the resin. A typical protocol involves addition of a wash solvent, shaking the resin with the solvent for five minutes and then removing the wash solvent from the reaction vessel. In many instances, the wash solvent is drained from the bottom of the reaction vessel by applying a vacuum, i.e., filtering the resin free of the waste solvent. The task is further complicated when multiple solid phase syntheses are simultaneously carried out.
For example, if each reaction vessel is to be subjected to a filtration step, performing separate filtration on each individual reaction vessel can be very time consuming. Alternatively, if filtering is to be performed on all of the reaction vessels simultaneously, this can lead to a very complicated and awkward arrangement of apparatus with, for example, each individual reaction vessel being connected to a vacuum source by a separate vacuum hose.
As described above, the waste liquid is flushed out during the washing cycles typically by vacuum filtration. During reaction cycles, however, the solvent and the reagents are to be retained in the reaction vessel which by design has a filter at the bottom. Previously, when batch filtering from several sources, each source was connected to the filter by a line with each line having a stop-cock or valve to regulate drainage.